Humpty Dumpty Had a Great Fall: Cessna SIDs

The Cessna SIDs have fluttered a few feathers in the aviation industry recently with much controversy surrounding their application, necessity and financial implications. In the interests of objectivity, our in-house pugnacious legal eagle takes an opposing view and considers their legal legitimacy in Australia and posits a possible alternative to wholescale disassembly.

A client of mine owns three Cessna aircraft of a certain age. I have flown with my client in one of these Cessnas and the flight was safe and pleasant. Recently, he received a series of documents, called “Supplemental Inspection Documents” (SIDs). The documents themselves consist of many pages of detailed inspections requiring the relevant Cessnas to be dismantled in their entirety, looked at by a LAME, and in some way given a clean bill of health or parts replaced appropriately, and signed off by a LAME. The SIDs are in addition to the normal 100 hourly inspections, periodic or major overhauls wherein the same aircraft have undergone the normal maintenance inspections during the life of the aircraft.

On the first blush of reading the SIDs, it seemed to be a second more comprehensive inspection virtually demolishing the aircraft to prove that the time in life inspections were done correctly. An interesting feature of the SIDs are that they have been compiled by the Cessna Airplane Manufacturing Company in the United States of America. The SIDs are not part of the manufacturer’s maintenance manual nor are they mandatory Cessna maintenance requirements under an FAA airworthiness directive or directives. Additionally, there are no CASA airworthiness directives giving the SIDs legal effect.

The whole exercise seems to be an expensive series of directives which are recommended or suggested that will cause a cautious owner to demolish his aircraft and put it together again after the inspection at great cost. Incidentally, the comparison cost of a new similar sized Cessna is much cheaper. Hey presto, the more cautious or money-conscious owner might be sorely tempted to send his SIDs expensive aircraft to the big touchdown in the sky and buy a new Cessna. It is to be noted that the Canadians have not adopted the “suggested” SIDs in their entirety. For that matter the FAA has done the same. This is not yet the case here, downunder: whilst CASA has not issued an AD they are policing this belts and braces SIDs inspection and presumably expect an owner to demolish his aircraft at his expense.

My client has bitten the bullet and written to CASA whose recent and encouraging statements that it will act reasonably in balancing necessary demands of safety and the imposition of expensive red tape for the sake of it seem to be tailor-made for a case such as this. Their prompt reply needs some deconstructing: “It is a regulatory requirement in Australia for aircraft to be maintained in accordance with approved maintenance data authorised by the aircraft manufacturer. SIDs were developed to ensure the on-going structural integrity of these aircraft which have continued to be operated for many decades beyond their original design service goals.”

This all seems sensible and safety-conscious enough and, one would assume, as Cessnas make up, by some margin, the largest aircraft type flying in our skies, that there are a fair number whose decriptude requires some sort of examination lest their ailments are inflicted upon the humans flying in them and the ones blithely wandering on the ground directly below.

However, from a legal standpoint, this response doesn’t necessarily hold water. Firstly, no one has ‘approved’ these SIDs in any legal way. The manufacturer has not put it into its maintenance manual or schedules. The FAA has not given them the legal gift of life with an AD. And the same with our own regulators – CASA has not breathed any legal life into the SIDS. There are no parallel airworthiness directives associated with these SIDs.

Secondly, how can it be said that by pulling the aircraft into a couple of thousand bits and then putting it together again like a meccano set that maintenance is being carried out? What does CASA think of the in-type life maintenance if the aircraft is to be dismantled completely a second time? It cannot be much.

So, is it to be suggested that the structural integrity of these aircraft is enhanced by stripping them back to a hangar full of aluminium skins and sundry bits and pieces. In what way does this process do anything for the safety of structural integrity? When the aircraft is reassembled, has structural integrity been vindicated or is it still in a state of maintenance doubt and suspension?

The concept of original design service goals (ODSG) is a novel feature of the legal system requiring an owner to adhere to the SIDs. When the DC3 was first built and flown in 1936, what authority gave it an original design service goal? DC3s are still flying around successfully without having to be pulled apart completely to comply with Douglas Airplane Company SIDs. I do not recall ever seeing an original design service goal set for any aircraft that I have flown. Furthermore, I remember flying a 1950 model F27 out of Luxembourg that was a better-rigged aircraft than the more modern 1970 models. So much for an original design service goal.

Let us assume that in some legitimate way the Cessna SIDs have some legal status with the ODSG superimposed in that status. The requirements to pull apart the ancient aircraft to determine if the ageing process requires a repair or two and then the aircraft is put together is very early 20th century in its concept.

However, let us also consider other ancients that have to be inspected to ensure that they do not fail because they have reached the limit of original design service goals. I am thinking of we humans.

It is said that the normal life span is three score years and ten i.e. 70 years. Anything beyond that is beyond the original design service goal. The medical profession certainly looks to see if perhaps corrosion has set in when one reaches 70 years. The medical profession uses the most innovative, technologically advanced gadgetry to carry out inspections and eradication of harmful impedimentia within an ancient human’s being without pulling the human apart. Let me be more specific.

Recently, your scribe, who is almost 80 years of age, was advised to have a colonoscopy. Having never considered such a procedure, I fronted a gastroenterologist, who told me about the possibility of polyps growing in my large intestine. It sounds very like corrosion growing in the insides of an aircraft. The gastroenterologist had a sophisticated probe that has a light, a camera that provides video images overhead and takes photographs of corrosive potentially cancerous polyps, a hot cutter and a catcher for bits to be pathologically examined.

It seems to be a multifaceted tool that could be adapted for probing into the nether regions of an ancient aircraft without having to dismantle the actual aircraft. When the gastroenterologist is inspecting my large intestine, which has gone beyond its original design service goal, he does not dismantle me and, after the inspection, put me together again.

Is there not an aviation equivalent of a borescope to inspect an aircraft? Is this such an obtuse idea because, let’s face it, once Humpty Dumpty is pulled apart, is it really worth putting him back together again?

1 comment

Peter RosendaleFebruary 1, 2016 - 10:46 am

I have last August’s issue of EAA magazine where FAA are explaining that what Cessna have done by introducing SIDS is illegal. When McCormack introduced SIDS he said “We are introducing SIDS at the request of owners, operators and maintainers”. Now Skidmore is stating that FAA and Cessna put the DIDS into practice. Both are incorrect! If Mr Skidmore was so concerned about aging aircraft, how come his 1947 Globe Swift is not required to have SIDS?
I brought 2 Cessna 150’s in Australia from the USA in 2010 and it cost me a lot of money to have everything checked out as it was being put on the Australian Registrar but guess what, I have to pay out again to have SIDS done. I am not going to just on principal and I would rather sell it at a loss overseas in Indonesia or the Philippines